Animals react much differently to products than humans do. Many products are safe for animals, but are ineffective and harmful to humans. For example, an arthritis drug called Vioxx killed more Americans than died in the Vietnam war. However, this drug was proved safe with eight animal tests done on six different species (Erbe 1). Also, animals have different internal structures than humans, and this can make a huge difference in whether the animal test is successful or not. In 1963-64, 13 humans received chimpanzee kidneys. 12 of the 13 people died within two months after their transplant ("Xenotransplantation" 1). This illustrates that the internal structures of even our closest relatives, chimpanzees, are still much different than our own. “Most animal experiments are done on animals that are nothing like human beings” (Dixon 1). Rats and mice share very little of our genes, but they are the most common animals tested on. This proves that animals react in a differently than humans, and products and medicines should be tested in some other way.